With rapid development of mobile networks, mobile networks have higher requirements on base station capacities, and a quantity of antennas on a base station is increasing. To reduce the quantity of antennas, an antenna capable of supporting multiple radio frequency (RF) modules (that is, multiple frequency bands) is put forward.
Generally, to perform, on an antenna, independent electrical tilt on RF signals sent by multiple RF modules, an on-off keying (OOK) modulation manner may be used. In this modulation manner, RF modules are respectively connected to corresponding phase shifters and different serial ports on a remote control unit (RCU) in an electrical tilt apparatus by using a bias tee (BT) built in the electrical tilt apparatus, and each of the RF modules sends an independent RF signal+electrical tilt signal (the electrical tilt signal includes an OOK signal and a direct current voltage signal), thereby implementing independent electrical tilt. For example, after receiving an RF signal+an electrical tilt signal sent by an RF module, an electrical tilt apparatus may separate the electrical tilt signal and the RF signal by using a built-in BT, input the RF signal to a phase shifter that corresponds to the RF module, and input the electrical tilt signal to an RCU. Then, the RCU controls, according to the electrical tilt signal, the phase shifter to move, to adjust a phase of the RF signal that is input to the phase shifter, and inputs the RF signal whose phase has been adjusted by using the phase shifter to an antenna element connected to the phase shifter, so that electrical tilt is performed on the RF signal sent by the RF module.
However, in the foregoing scenario in which an electrical tilt apparatus performs independent electrical tilt on RF signals sent by multiple RF modules, because the RF modules need to connect to different serial ports on an RCU in the electrical tilt apparatus, a quantity of the serial ports on the RCU needs to be greater than or equal to a quantity of the RF modules. However, because a quantity of serial ports on an RCU is usually limited (usually three or four) in reality, when a quantity of RF modules exceeds the quantity of the serial ports on the RCU, the electrical tilt apparatus cannot implement independent electrical tilt on RF signals sent by some RF modules.